The present invention is directed to compounds and their pharmaceutically acceptable salts, which inhibit matrix metalloproteases, and are therefore useful in the treatment of mammals having disease-states alleviated by the inhibition of such matrix metalloproteases.
Matrix metalloproteases (xe2x80x9cMMPs)xe2x80x9d are a family of proteases (enzymes) involved in the degradation and remodeling of connective tissues. Members of this family of endopeptidase enzymes are present in various cell types that reside in or are associated with connective tissue, such as fibroblasts, monocytes, macrophages, endothelial cells, and invasive or metastatic tumor cells. MMP expression is stimulated by growth factors and cytokines in the local tissue environment, where these enzymes act to specifically degrade protein components of the extracellular matrix, such as collagen, proteoglycans (protein core), fibronectin and laminin. These ubiquitous extracellular matrix components are present in the linings of joints, interstitial connective tissues, basement membranes, and cartilage. Excessive degradation of extracellular matrix by MMPs is implicated in the pathogenesis of many diseases, including rheumatoid arthritis, osteoarthritis, periodontal disease, aberrant angiogenesis, tumor invasion and metastasis, corneal ulceration, and in complications of diabetes. MMP inhibition is, therefore, recognized as a good target for therapeutic intervention.
The MMPs share a number of properties, including zinc and calcium dependence, secretion as zymogens, and 40-50% amino acid sequence homology. The MMP family includes collagenases, stromelysins, gelatinases, and matrilysin, as discussed in greater detail below.
Interstitial collagenases catalyze the initial and rate-limiting cleavage of native collagen types I, II, III and X. Collagen, the major structural protein of mammals, is an essential component of the matrix of many tissues, for example, cartilage, bone, tendon a skin. Interstitial collagenases are very specific matrix metalloproteases which cleave collagen to give two fragments which spontaneously denature at physiological temperatures and therefore become susceptible to cleavage by less specific enzymes. Cleavage by the collagenase results in the loss of structural integrity of the target tissue, essentially an irreversible process.
The gelatinases include two distinct, but highly related, enzymes: a 72-kD enzyme secreted by fibroblasts and a wide variety of other cell types, and a 92-kD enzyme released by mononuclear phagocytes, neutrophils, corneal epithelial cells, tumor cells, cytotrophoblasts and keratinocytes. These gelatinases have been shown to degrade gelatins (denatured collagens), collagen types IV (basement membrane) and V, fibronectin and insoluble elastin.
The stromelysins (1 and 2) have been shown to cleave a broad range of matrix substrates, including laminin, fibronectin, proteoglycans, and collagen types IV and IX in their non-helical domains.
Matrilysin (putative metalloprotease or PUMP) is a recently described member of the matrix metalloprotease family. Matrilysin has been shown to degrade a wide range of matrix substrates including proteoglycans, gelatins, fibronectin, elastin, and laminin. Its expression has been documented in mononuclear phagocytes, rat uterine explants and sporadically in tumors.
Inhibitors of MMPs provide useful treatments for diseases associated with the excessive degradation of extracellular matrix, such as arthritic diseases (rheumatoid arthritis and osteoarthritis), bone resorptive diseases (such as osteoporosis), the enhanced collagen destruction associated with diabetes, periodontal disease, corneal ulceration, ulceration of the skin, tumor invasion and metastasis, and aberrant angiogenesis.
The design and uses of MMP inhibitors is described, for example, in J. Enzyme Inhibition (1987), Vol. 2, pp. 1-22; Drug News and Prospectives (1990), Vol. 3, No. 8, pp. 453-458; Arthritis and Rheumatism (1993), Vol. 36, No. 2, pp. 181-189; Arthritis and Rheumatism (1991), Vol. 34, No. 9, pp. 1073-1075; Seminars in Arthritis and Rheumatism (1990), Vol. 19, No. 4, Supplement 1 (February), pp. 16-20; Drugs of the Future (1990), Vol. 15, No. 5, pp. 495-508; and J. Enzyme Inhibition (1987), Vol. 2, pp. 1-22. MMP inhibitors are also the subject of various patents and patent applications, for example, U.S. Pat. No. 5,189,178 (Galardy) and U.S. Pat. No. 5,183,900 (Galardy), European Published Patent Applications 0 438 223 (Beecham) and 0 276 436 (F. Hoffmann-La Roche), and Patent Cooperation Treaty International Applications 92/21360 (Merck), 92/06966 (Beecham) and 92/09563 (Glycomed).
The invention provides new compounds which are useful as inhibitors of matrix metalloproteases and which are effective in treating disease-states characterized by excessive activity of matrix metalloproteases.
Accordingly, one aspect of the invention is directed to compounds of formula (I): 
wherein:
R1 is mercapto, acetylthio, carboxy, hydroxycarbamoyl, N-hydroxyformamide, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, benzyloxycarbamoyl or a group of the formula 
xe2x80x83where R6 is aryl or heteroaryl;
R2 is alkyl, cycloalkyl, aryl, heterocycloalkyl, or heteroaryl;
R3 is alkyl, cycloalkyl, aralkyl, or heteroaralkyl;
R7 is aryl, heteroaryl or heterocycloalkyl;
X is a group of the formula xe2x80x94(CH2)mxe2x80x94Yxe2x80x94(CH2)nxe2x80x94, where:
Y is O, S, or a single bond,
m is an integer from 0 to 4,
n is an integer from 0 to 4, and
m+n is an integer from 0 to 4;
p is an integer from 0 to 4, provided that R2xe2x80x94X is biphenylalkyl when
p is not 0;
and the pharmaceutically acceptable salts thereof.
Another aspect of the invention provides processes for synthesizing the compounds and salts of formula (I).
In another aspect, the invention is directed to a sub-genus of formula (I), i.e., the compounds of formula (II), as follows: 
wherein:
R1 is mercapto, acetylthio, carboxy, hydroxycarbamoyl, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, benzyloxyaminocarbonyl or a group of the formula 
xe2x80x83where R6 is aryl or heteroaryl;
R2 is alkyl, aralkyl or cycloalkylalkyl;
R3 is cycloalkyl, alkyl (optionally substituted by cycloalkyl, hydroxy, mercapto, alkylthio, aralkoxy, carboxy, amino, alkylamino, guanidino, carbamoyl, pyridinyl or indolyl), or aralkyl (optionally substituted by hydroxy, carboxy, alkyl or alkoxy);
R4 is nitro, amino, cyano, hydroxy, alkoxy, carboxy, alkoxycarbonyl, alkylsulfonyl, haloalkyl, alkoxycarbonylalkyl, tetrazolyl, carbamoyl (optionally substituted by alkyl or dialkylaminoalkyl), or aminosulfonyl (optionally substituted by alkyl); and
R5 is hydrogen, halo or hydroxy,
as a single stereoisomer or as a mixture thereof; and the pharmaceutically acceptable salts thereof.
Another aspect of the invention is directed to compounds of the formula 
wherein:
R2 is alkyl, aryl or heteroaryl; and
X is a group of the formula xe2x80x94(CH2)mxe2x80x94Yxe2x80x94(CH2)n, where:
Y is O, S, or a single bond,
m is an integer from 0 to 4,
n is an integer from 0 to 4, and
m+n is an integer from 0 to 4;
or R2 and X together are lower alkenyl.
Another aspect of the invention is directed to processes for synthesizing a compound of the formula 
wherein R2 is aryl or heteroaryl, by
(a) hydrogenating a compound of the formula: 
xe2x80x83in the presence of a palladium/carbon catalyst; or
(b) contacting a compound of the formula 
xe2x80x83with sodium hexamethyldisilazide and t-butylbromoacetate.
Other aspects of the invention are directed to compounds of the formula 
wherein R2 is aryl or heteroaryl, and a process for synthesizing these compounds by
(a) contacting a compound of the formula: 
xe2x80x83where R2 is hydrogen, aryl or heteroaryl, with an excess of mesyl chloride in pyridine followed by refluxing under basic conditions, and
(b) where R2 is hydrogen in step (a), reacting the product of step (a) with an aryl halide or a heteroaryl halide in the presence of a base and a palladium catalyst.
Another aspect of the invention is directed to methods of inhibiting matrix metalloprotease activity in a mammal, which methods comprise administering to the mammal in need thereof a therapeutically effective amount of a compound of formula (I) as defined above, as a single stereoisomer, or as a mixture thereof, or a pharmaceutically acceptable salt thereof.
Another aspect of the invention is directed to a pharmaceutical composition useful in inhibiting matrix metalloprotease activity in a mammal, which composition comprises a therapeutically effective amount of a compound of formula (I) as defined above, as a single stereoisomer or as a mixture thereof; or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable excipient.
As used in the specification and appended claims, unless specified to the contrary, the following terms have the meaning indicated:
xe2x80x9cBOCxe2x80x9d refers to t-butoxycarbonyl.
xe2x80x9cCBZxe2x80x9d refers to benzyloxycarbonyl (carbobenzyloxy).
xe2x80x9cDCCxe2x80x9d refers to N,N-dicyclohexylcarbodiimide.
xe2x80x9cDMAPxe2x80x9d refers to N,N-dimethylaminopyridine.
xe2x80x9cDMFxe2x80x9d refers to N,N-dimethylformamide.
xe2x80x9cEDCIxe2x80x9d refers to N-ethyl-Nxe2x80x2-(3-dimethylaminopropyl)-carbodiimide.
xe2x80x9cHOBTxe2x80x9d refers to 1-hydroxybenzotriazole.
xe2x80x9cHydroxyxe2x80x9d refers to the radical xe2x80x94OH.
xe2x80x9cAminoxe2x80x9d refers to the radical xe2x80x94NH2.
xe2x80x9cAcetylthioxe2x80x9d refers to the radical xe2x80x94SC(O)CH3.
xe2x80x9cHaloxe2x80x9d refers to bromo, chloro or fluoro.
xe2x80x9cCarbamoylxe2x80x9d refers to the radical xe2x80x94C(O)NH2.
xe2x80x9cCarboxyxe2x80x9d refers to the radical xe2x80x94C(O)OH.
xe2x80x9cHydroxyaminoxe2x80x9d refers to the radical xe2x80x94NHOH.
xe2x80x9cHydroxycarbamoylxe2x80x9d refers to the radical xe2x80x94C(O)NHOH.
xe2x80x9cN-Hydroxyformamidexe2x80x9d refers to the radical xe2x80x94N(OH)C(O)H
xe2x80x9cBenzyloxycarbamoylxe2x80x9d refers to xe2x80x94C(O)N(H)OCH2C6H5.
xe2x80x9cAcylamidexe2x80x9d refers to xe2x80x94NHC(O)Ra where Ra is alkyl.
xe2x80x9cMercaptoxe2x80x9d refers to the radical xe2x80x94SH.
xe2x80x9cAlkylxe2x80x9d refers to a straight or branched chain monovalent radical consisting solely of carbon and hydrogen, containing no unsaturation and having from one to ten carbon atoms, e.g., methyl, ethyl, n-propyl, 2-methylpropyl (iso-butyl), 1-methylethyl (iso-propyl), n-butyl, and 1,1-dimethylethyl (t-butyl), heptyl and the like, which can be optionally substituted by cycloalkyl, hydroxy, mercapto, alkylthio, aralkoxy, carboxy, amino, mono- and di-alkylamino, guanidino, N,N-dialkylguanidino, carbamoyl, aryl, and heteroaryl.
xe2x80x9cAlkanylxe2x80x9d or xe2x80x9calkylenexe2x80x9d refers to a straight chain divalent radical consisting solely of carbon and hydrogen, containing no unsaturation and having from one to five carbon atoms, e.g., methylene, ethylene, propylene (or propanyl) and the like.
xe2x80x9cLower alkenylxe2x80x9d refers to a straight chain univalent hydrocarbon radical having from two to six carbon atoms and containing at least one unsaturated bond, e.g., prop-2-enyl, pent-4-enyl and the like.
xe2x80x9cAlkylaminoxe2x80x9d refers to a radical of the formula xe2x80x94NHRa where Ra is alkyl as defined above, e.g., methylamino, ethylamino, iso-propylamino, n-butylamino, and the like.
xe2x80x9cHaloalkylxe2x80x9d refers to a radical of the formula xe2x80x94RaRd where Ra is alkyl as defined above substituted by one or more halo groups (Rd) as defined above, e.g., 2-chloroethyl, 2-bromoethyl, trifluoromethyl, and the like.
xe2x80x9cDialkylaminoalkylxe2x80x9d refers to a radical of the formula xe2x80x94RaN(Ra)2 where each Ra is independently an alkyl radical as defined above, e.g., dimethyl-aminoethyl, diethylamino-n-propyl, dimethylamino-n-propyl, and the like.
xe2x80x9cAminosulfonylxe2x80x9d refers to xe2x80x94S(O)2NH2.
xe2x80x9cAlkylsulfonylxe2x80x9d refers to a radical of the formula xe2x80x94S(O)2Ra where Ra is alkyl as defined above, e.g., methylsulfonyl, ethylsulfonyl, iso-propylsulfonyl, and the like.
xe2x80x9cAlkylsulfinylxe2x80x9d refers to a radical of the formula xe2x80x94S(O)Ra where Ra is alkyl as defined above.
xe2x80x9cAlkylthioxe2x80x9d refers to a radical of the formula xe2x80x94SRa where Ra is optionally-substituted alkyl as defined above, e.g., methylthio, ethylthio, iso-propylthio, n-butylthio, and the like.
xe2x80x9cAlkoxyxe2x80x9d refers to a radical of the formula xe2x80x94ORa wherein Ra is alkyl as defined above, e.g., methoxy, ethoxy, n-propoxy, 1-methylethoxy, n-butoxy, t-butoxy, and the like.
xe2x80x9cAlkoxycarbonylalkylxe2x80x9d refers to a radical of the formula xe2x80x94RaC(O)Rb where Ra is alkyl as defined above and Rb is alkoxy as defined above, e g., methoxycarbonylethyl, ethoxycarbonylethyl, methoxycarbonyl-iso-propyl, and the like.
xe2x80x9cArylxe2x80x9d refers to a monovalent unsaturated aromatic carbocyclic radical having a single ring (e.g., phenyl), two condensed rings (e.g., naphthyl) or three condensed rings (e.g., phenanthrenyl or fluorenyl) which can be optionally substituted by one or more substituents independently selected from: alkyl, hydroxy, carboxy, halo, cyano, amino, nitro, tetrazolyl, heteroaryl, aminoalkoxy, alkylthio, haloalkyl, alkoxy, alkoxycarbonyl, alkoxycarbonylalkyl, alkyl sulfonyl, alkyl sulfinyl, aminosulfonyl optionally substituted by alkyl, carbamoyl optionally substituted by alkyl or dialkylaminoalkyl, or the substituent can be another aryl group as defined herein (e.g., to form an optionally substituted biphenyl radical).
xe2x80x9cAryloxyxe2x80x9d refers to a radical of the formula xe2x80x94ORb wherein Rb is aryl as defined above, e.g., phenoxy, quinol-2-yloxy, naphth-1-yloxy, or naphth-2-yloxy.
xe2x80x9cAralkylxe2x80x9d refers to a radical of the formula xe2x80x94RaRb wherein Ra is alkyl as defined above and Rb is aryl as defined above, e.g., benzyl, phenylethylene, 3-phenylpropyl, and the like.
xe2x80x9cAralkoxyxe2x80x9d refers to a radical of the formula xe2x80x94ORaRb wherein Ra is alkyl as defined above and Rb is aryl as defined above, e.g., benzyloxy, 3-naphth-2-ylpropoxy, and the like.
xe2x80x9cAlkoxycarbonylxe2x80x9d refers to a radical of the formula xe2x80x94C(O)Rb wherein Rb is alkoxy as defined above, e.g., methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl, and the like.
xe2x80x9cAralkoxycarbonylxe2x80x9d refers to a radical of the formula xe2x80x94C(O)Rc wherein Rc is aralkoxy as defined above, e.g., benzyloxycarbonyl, and the like.
xe2x80x9cCycloalkylxe2x80x9d refers to a monovalent ring radical consisting solely of carbon and hydrogen atoms, containing no unsaturation and having from five to seven carbon atoms, e.g., cyclopentyl, cyclohexyl and cycloheptyl.
xe2x80x9cCycloalkylalkylxe2x80x9d refers to a radical of the formula xe2x80x94RcRa where Ra is alkyl as defined above and Rc is cycloalkyl as defined above, e.g., cyclohexylmethyl, cyclohexylethyl, cyclopentylmethyl, and the like.
xe2x80x9cHeteroarylxe2x80x9d refers to a monovalent unsaturated aromatic carbocyclic radical having a single ring or multiple condensed rings with at least one heteroatom such as N,O,S, (e.g., pyridyl, quinolyl, indolyl, carbazolyl, dibenzofuranyl, dibenzothiophenyl, phenanthridinyl), which can be optionally substituted by one or more substituents independently selected from: alkyl, hydroxy, carboxy, halo, cyano, amino, nitro, tetrazolyl, aryl, aminoalkoxy, alkylthio, haloalkyl, alkoxy, alkoxycarbonyl, alkoxycarbonylalkyl, alkyl sulfonyl, alkyl sulfinyl, aminosulfonyl optionally substituted by alkyl, and carbamoyl optionally substituted by alkyl or dialkylaminoalkyl.
xe2x80x9cHeteroaralkylxe2x80x9d refers to a radical of the formula xe2x80x94RaRb where Ra is alkyl as defined above and Rb is heteroaryl as defined above.
xe2x80x9cHeterocycloalkylxe2x80x9d refers to a monovalent saturated carbocyclic radical having a single ring or multiple condensed rings with at least one heteroatom such as N,O,S (e.g., morpholino, piperazinyl, piperidinyl, pyrrolidinyl).
xe2x80x9cOptionalxe2x80x9d or xe2x80x9coptionallyxe2x80x9d means that the subsequently described event of circumstances may or may not occur, and that the description includes instances where said event or circumstance occurs and instances in which it does not. For example, xe2x80x9coptionally substituted quinol-2-ylxe2x80x9d means that the quinol-2-yl radical may or may not be substituted and that the description includes both substituted quinol-2-yl radicals and quinol-2-yl radicals having no substitution.
xe2x80x9cAmino-protecting groupxe2x80x9d as used herein refers to those organic groups intended to protect nitrogen atoms against undesirable reactions during synthetic procedures, and includes, but is not limited to, benzyl, acyl, acetyl, benzyloxycarbonyl (carbobenzyloxy), p-methoxybenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, t-butoxycarbonyl, trifluoroacetyl, and the like.
xe2x80x9cBasexe2x80x9d as used here includes both strong bases such as sodium hydroxide, lithium hydroxide, ammonium hydroxide, potassium carbonate and the like, and organic bases such as pyridine, diisopropylethylamine, N-methylmorpholine, triethylamine, dimethylaminopyridine and the like.
xe2x80x9cPharmaceutically acceptable saltxe2x80x9d refers to those salts which retain the biological effectiveness and properties of the free bases or free acids and which are not biologically or otherwise undesirable. If the compound exists as a free base, the desired salt may be prepared by methods known to those of ordinary skill in the art, such as treatment of the compound with an inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid and the like; or with an organic acids such as acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, and the like. If the compound exists as a free acid, the desired salt may also be prepared by methods known to those of ordinary skill in the art, such as the treatment of the compound with an inorganic base or an organic base. Salts derived from inorganic bases include, but are not limited to, the sodium, potassium, lithium, ammonium, calcium, magnesium, iron, zinc, copper, manganese, aluminum salts and the like. Salts derived from organic bases include, but are not limited to, salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines and basic ion exchange resins, such as isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, ethanolamine, 2-dimethylaminoethanol, 2-diethylaminoethanol, trimethamine, dicyclohexylamine, lysine, arginine, histidine, caffeine, procaine, hydrabamine, choline, betaine, ethylenediamine, glucosamine, methylglucamine, theobromine, purines, piperazine, piperidine, N-ethylpiperidine, polyamine resins and the like.
xe2x80x9cMammalxe2x80x9d includes humans and all domestic and wild animals, including, without limitation, cattle, horses, swine, sheep, goats, dogs, cats, and the like.
xe2x80x9cTherapeutically effective amountxe2x80x9d refers to that amount of a compound of formula (I) which, when administered to a mammal in need thereof, is sufficient to effect treatment, as defined below, for disease-states alleviated by the inhibition of matrix metalloprotease activity, such as the activity of stromelysin, gelatinase, matrilysin and/or collagenase. The amount of a compound of formula (I) which constitutes a xe2x80x9ctherapeutically effective amountxe2x80x9d will vary depending on the compound, the disease-state and its severity, and the mammal to be treated, but can be determined routinely by one of ordinary skill in the art having regard to his own knowledge and to this disclosure.
xe2x80x9cTreatingxe2x80x9d or xe2x80x9ctreatmentxe2x80x9d as used herein cover the treatment of a disease-state in a mammal, particularly in a human, which disease-state is alleviated by the inhibition of matrix metalloprotease activity, such as the activity of stromelysin, gelatinase, matrilysin and/or collagenase, and include:
(i) preventing the disease-state from occurring in a mammal, in particular, when such mammal is predisposed to the disease-state but has not yet been diagnosed as having it;
(ii) inhibiting the disease-state, i.e., arresting its development; or
(iii) relieving the disease-state, i.e., causing regression of the disease-state.
xe2x80x9cStereoisomersxe2x80x9d refers to compounds having identical molecular formulae and nature or sequence of bonding but differing in the arrangement of their atoms in space.
The compounds of formula (I), or their pharmaceutically acceptable salts, have at least two asymmetric carbon atoms in their structure, and may therefore exist as single stereoisomers, racemates, and as mixtures of enantiomers and diastereomers. All such single stereoisomers, racemates and mixtures thereof are intended to be within the scope of this invention.
When naming the single stereoisomers of compounds of formula (I) an absolute descriptor, R or S, may be assigned to the chiral carbon atoms therein according to the xe2x80x9cSequence Rulexe2x80x9d procedure of Cahn, Ingold and Prelog.
The nomenclature used herein is a modified form of I.U.P.A.C. nomenclature wherein the compounds of the invention are named as peptide derivatives. Where R3 of Formula (I) comprises the side chain of an amino acid residue, that portion of the chemical structure which includes R3 together with the adjacent nitrogen atom (illustrated below and named as the N nitrogen, as opposed to the Nxe2x80x2 nitrogen) and carbonyl group is given the name of the corresponding amino acid. The naming and numbering of the compounds of the present invention is illustrated below for representative compounds of formula (I).
For example, the following compound of formula (I) 
wherein R1 is carboxy; R2 is biphenyl; R3 is 4-(cyano)benzylthioisopropyl; R7 is phenyl; X is propanyl; and p is 0, is named N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-S-((4-cyanophenyl)methyl)-penicillamine-Nxe2x80x2-(phenyl)carboxamide. Another name for this compound is N-(5-(biphen-4-yl)-2R-carboxymethylpentanoyl)-L-S-((4-cyanophenyl)methyl)-penicillamine-Nxe2x80x2-(phenyl)carboxamide. For ease of reference, the portions of the structure are associated with their corresponding nomenclature.
The structures and names of several other representative compounds of formula (I) follow. 
The above compound is named N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-t-butylglycine-Nxe2x80x2-(pyrid-4-yl)carboxamide. The term t-leucine can be interchanged with t-butylglycine, and the term pyridinyl can be interchanged with pyridyl. Another name for the above compound is: N-(5-biphen-4-yl-2R-carboxymethylpentanoyl)-L-t-leucine-Nxe2x80x2-(pyridin-4-yl)carboxamide. 
The above compound is named N-(2R-carboxymethyl-5-(7-(glycyl)aminofluoren-2-yl)pentanoyl)-L-leucine-Nxe2x80x2-(4-(methoxycarbonyl)phenyl)carboxamide. Another name for this compound is N-(5-(7-(glycyl)aminofluoren-2-yl)-2R-carboxymethylpentanoyl)-L-leucine-Nxe2x80x2-(4-methoxycarbonylphenyl)carboxamide. 
The above compound is named N-(2R-carboxymethyl-5-(phenyl)pentanoyl-L-6-(N,Nxe2x80x2-diethylguanido)lysyl-Nxe2x80x2-(4-(ethoxycarbonyl)phenyl)carboxamide. The term guanidino can be used interchangeably with guanido. Another name for this compound is N-(5-phenyl-2R-carboxymethylpentanoyl)-L-6-(N,Nxe2x80x2-diethylguanidino)-lysyl-Nxe2x80x2-(4-ethoxycarbonylphenyl)carboxamide. 
The above compound is named N-(2R-(Nxe2x80x3-formyl-Nxe2x80x3-hydroxyamino)methyl-4-((3-chloro,5-morpholino)phen-1-yl)oxybutanoyl)-L-cyclohexylglycine-Nxe2x80x2-(4-(indol-5-yl)butyl)carboxamide. Another name for this compound is N-(4-((3-chloro,5-morpholino)phen-1-yl)-2R-(Nxe2x80x3-formyl-Nxe2x80x3-hydroxyamino)methyloxybutanoyl)-L-cyclohexylglycine-Nxe2x80x2-(4-(indol-5-yl)butyl)carboxamide.
Utility
The compounds of formula (I) inhibit mammalian matrix metalloproteases, such as the stromelysins, gelatinases, matrilysin and collagenases, and are therefore useful for treating diseases associated with the MMP-induced excessive degradation of matrix and connective tissue within the mammal, for example, arthritic diseases (rheumatoid arthritis and osteoarthritis), bone resorptive diseases (such as osteoporosis), the enhanced collagen destruction associated with diabetes, periodontal disease, corneas ulceration, ulceration of the skin, tumor invasion and metastasis, and aberrant angiogenesis.
Testing
The ability of the compounds of formula (I) to inhibit matrix metalloprotease activity, such as the activity of stromelysin, gelatinase, matrilysin and/or collagenase may be demonstrated by a variety of in vitro and in vivo assays known to those of ordinary skill in the art, such as the assay described in Anal. Biochem. (1985), Vol. 147, p. 437, and the MMP Enzymatic Assay described in FEBS (1992), Vol. 296(3), p. 263, or modifications thereof.
Administration
Administration of the compounds of formula (I), or their pharmaceutically acceptable salts, in pure form or in an appropriate pharmaceutical composition, can be carried out via any of the accepted modes of administration or agents for serving similar utilities. Thus, administration can be, for example, orally, nasally, parenterally, topically, transdermally, or rectally, in the form of solid, semi-solid, lyophilized powder, or liquid dosage forms, such as for example, tablets, suppositories, pills, soft elastic and hard gelatin capsules, powders, solutions, suspensions, or aerosols, or the like, preferably in unit dosage forms suitable for simple administration of precise dosages. The compositions will include a conventional pharmaceutical carrier or excipient and a compound of formula (I) as the/an active agent, and, in addition, may include other medicinal agents, pharmaceutical agents, carriers, adjuvants, etc.
Generally, depending on the intended mode of administration, the pharmaceutically acceptable compositions will contain about 1% to about 99% by weight of a compound(s) of formula (I), or a pharmaceutically acceptable salt thereof, and 99% to 1% by weight of a suitable pharmaceutical excipient. Preferably, the composition will be about 5% to 75% by weight of a compound(s) of formula (I), or a pharmaceutically acceptable salt thereof, with the rest being suitable pharmaceutical excipients.
The preferred route of administration is oral, using a convenient daily dosage regimen which can be adjusted according to the degree of severity of the disease-state to be treated. For such oral administration, a pharmaceutically acceptable composition containing a compound(s) of formula (I), or a pharmaceutically acceptable salt thereof, is formed by the incorporation of any of the normally employed excipients, such as, for example, pharmaceutical grades of mannitol, lactose, starch, pregelatinized starch, magnesium stearate, sodium saccharine, talcum, cellulose ether derivatives, glucose, gelatin, sucrose, citrate, propyl gallate, and the like. Such compositions take the form of solutions, suspensions, tablets, pills, capsules, powders, sustained release formulations and the like.
Preferably such compositions will take the form of capsule, caplet or tablet and therefore will also contain a diluent such as lactose, sucrose, dicalcium phosphate, and the like; a disintegrant such as croscarmellose sodium or derivatives thereof; a lubricant such as magnesium stearate and the like; and a binder such as a starch, gum acacia, polyvinylpyrrolidone, gelatin; cellulose ether derivatives, and the like.
The compounds of formula (I), or their pharmaceutically acceptable salts, may also be formulated into a suppository using, for example, about 0.5% to about 50% active ingredient disposed in a carrier that slowly dissolves within the body, e.g., polyoxyethylene glycols and polyethylene glycols (PEG), e.g., PEG 1000 (96%) and PEG 4000 (4%).
Liquid pharmaceutically administrable compositions can, for example, be prepared by dissolving, dispersing, etc., a compound(s) of formula (I) (about 0.5% to about 20%), or a pharmaceutically acceptable salt thereof, and optional pharmaceutical adjuvants in a carrier, such as, for example, water, saline, aqueous dextrose, glycerol, ethanol and the like, to thereby form a solution or suspension.
If desired, a pharmaceutical composition of the invention may also contain minor amounts of auxiliary substances such as wetting or emulsifying agents, Ph buffering agents, antioxidants, and the like, such as, for example, citric acid, sorbitan monolaurate, triethanolamine oleate, butylated hydroxytoluene, etc.
Actual methods of preparing such dosage forms are known, or will be apparent, to those skilled in this art; for example, see Remington""s Pharmaceutical Sciences, 18th Ed., (Mack Publishing Company, Easton, Pa., 1990). The composition to be administered will, in any event, contain a therapeutically effective amount of a compound of formula (I), or a pharmaceutically acceptable salt thereof, for treatment of a disease-state alleviated by the inhibition of matrix metalloprotease activity in accordance with the teachings of this invention.
The compounds of formula (I), or their pharmaceutically acceptable salts, are administered in a therapeutically effective amount which will vary depending upon a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of the compound, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular disease-state, and the host undergoing therapy.
Generally, a therapeutically effective daily dose is from about 0.14 mg to about 14.3 mg/kg of body weight per day of a compound of formula (I), or a pharmaceutically acceptable salt thereof; preferably, from about 0.7 mg to about 10 mg/kg of body weight per day; and most preferably, from about 1.4 mg to about 7.2 mg/kg of body weight per day. For example, for administration to a 70 kg person, the dosage range would be from about 10 mg to about 1.0 gram per day of a compound of formula (I), or a pharmaceutically acceptable salt thereof, preferably from about 50 mg to about 700 mg per day, and most preferably from about 100 mg to about 500 mg per day.
Preferred are the compounds of formula (I) where X is alkanyl and where p is zero, 2 or 3.
Of the compounds where p is 2 or 3, particularly preferred are those compounds where R1 is carboxy, R2 is biphenyl, R3 is cyclohexyl, and R7 is optionally substituted phenyl [especially 4-(aminosulfonyl)phenyl] or N-morpholino.
Of the compounds where p is zero, particularly preferred are the group of compounds where R2 is alkyl, optionally substituted phenyl, or a group of the formula: 
and R7 is 4-pyridyl or optionally substituted phenyl.
Within this group, a preferred subgroup of compounds are those where R1 is carboxy, hydroxycarbamoyl, or N-hydroxyformamide; R2 is phenyl, biphenyl, 4-(pyridyl)phenyl, or 2-methylpropyl; R3 is t-butyl, 4-aminobutyl, alkylaminobutyl, dialkylaminobutyl, 4-(N,Nxe2x80x2diethylguanidino)butyl, propyl, 2-methylpropyl, 1-hydroxyisopropyl, 1-hydroxyethyl, or cyclohexyl; and X is a single bond, ethylene or propanyl.
Within this subgroup, a preferred class of compounds are those where R2 is biphenyl, R3 is t-butyl and R7 is 4-pyridyl, particularly where R1 is carboxy, N-hydroxyformamide, or hydroxycarbamoyl.
Also preferred is the subgroup of compounds where R2 is a group of the formula: 
where A is CH2; R10 is H or acylamide; R11 is H; R7 is optionally substituted phenyl; and X is propanyl.
Within this subgroup, preferred are the compounds where R1 is carboxy, hydroxycarbamoyl, or N-hydroxyformamide; R3 is alkyl (especially 2-methylpropyl); and R7 is alkoxycarbonylphenyl [especially 4-(methoxycarbonyl)phenyl].
Also within this group, preferred are the subgroup of compounds where R1 is carboxy; R2 is phenyl; R3 is alkyl [especially 4-(amino)butyl and 4-(diethylguanidino)N-butyl] or cycloalkyl (especially cyclohexyl); and R7 is optionally substituted phenyl [especially 4-(ethoxycarbonyl)phenyl or 4-(dialkylaminoethylaminosulfonyl)phenyl]; and X is ethylene or propanyl.
Also within this group, preferred are the subgroup of compounds where R1 is mercapto, carboxy, hydroxycarbamoyl, or N-hydroxyformamide; R2 is 2-methylpropyl; R3 is alkyl [especially propyl, 2-methylpropyl], cycloalkyl [especially cyclohexyl] or heteroaralkyl [especially 3-methylindolyl]; R7 is optionally substituted phenyl [especially 4-(methoxy)phenyl, 4-(carboxy)phenyl, 4-(methoxycarbonyl)phenyl or 4-(dimethylaminoethylcarbamoyl)phenyl]; and X is a single bond.
Also within this group, preferred are the subgroup of compounds where R1 is carboxy; R2 is 4-(2-hydroxyethyl)phenyl, 4-(2-hydroxypropyl)-phenyl, 4-(2-hydroxybutyl)phenyl, 4-(pyridyl)phenyl, biphenyl, 4xe2x80x2-(aminoethoxy)biphenyl, 4xe2x80x2-(cyano)biphenyl, or 4xe2x80x2-(hydroxy)biphenyl; R3 is 2-methylpropyl; R7 is 4-(methoxycarbonyl)phenyl; and X is propanyl.
Particularly preferred is the subgroup of compounds where R2 is biphenyl, especially where R7 is optionally substituted phenyl.
Within this particularly preferred subgroup, preferred are the compounds where R1 is carboxy; R3 is alkyl or cycloalkyl [especially cyclohexyl, 4-(amino)butyl, 4-(isopropylamino)butyl, 1-hydroxyisopropyl or t-butyl]; X is propanyl, and R7 is phenyl, 4-(hydroxyethylaminosulfonyl)phenyl, 4-(dimethylaminoethyl-aminosulfonyl)phenyl, 4-(ethoxycarbonyl)phenyl, 4-(N-morpholinopropylaminosulfonyl)phenyl, 4-(methylaminosulfonyl)phenyl, 4-(hydroxyethylaminosulfonyl)phenyl, or 4-(methylsulfinyl)phenyl.
Another preferred group, particularly for matrilysin inhibition, are the compounds of formula (II), particularly those compounds wherein R1 is mercapto or acetylthio.
Within this second group, a preferred subgroup of compounds are those compounds wherein R2 is alkyl, aralkyl, cycloalkylalkyl; R3 is cycloalkyl or alkyl (optionally substituted by cycloalkyl, hydroxy, aralkoxy, alkylthio, pyridinyl or indolyl); R4 is cyano, carboxy, hydroxy, alkoxy, alkoxycarbonyl, alkoxycarbonylalkyl, carbamoyl (optionally substituted by aralkylaminoalkyl), or aminosulfonyl (optionally substituted by alkyl); and R5 is hydrogen.
Within this subgroup, a preferred class of compounds are those compounds wherein R2 is alkyl; R3 is cyclohexyl, alkyl (optionally substituted by cyclohexyl, hydroxy, benzyloxy, methylthio, pyridinyl or indolyl); and R4 is carboxy, alkoxycarbonyl and aminosulfonyl.
Within this class of compounds, compounds wherein R2 is 2-methylpropyl are preferred. Particularly preferred are those compounds wherein R3 is 2-methylpropyl.
A third group preferred for matrilysin inhibition, are the compounds of formula (II) wherein R1 is carboxy.
Within this third group, a preferred subgroup of compounds are those compounds wherein R2 is alkyl, aralkyl, cycloalkylalkyl; R3 is cycloalkyl or alkyl (optionally substituted by cycloalkyl, hydroxy, aralkoxy, alkylthio, pyridinyl or indolyl); R4 is cyano, hydroxy, alkoxy, carboxy, alkoxycarbonyl, alkoxycarbonylalkyl, carbamoyl (optionally substituted by aralkylaminoalkyl), or aminosulfonyl (optionally substituted by alkyl); and R5 is hydrogen.
Within this subgroup, a preferred class of compounds are those compounds wherein R2 is alkyl; R3 is cyclohexyl, alkyl (optionally substituted by cyclohexyl, hydroxy, benzyloxy, methylthio, pyridinyl or indolyl); and R4 is carboxy, alkoxycarbonyl and aminosulfonyl.
Within this class of compounds, preferred compounds are those compounds wherein R2 is 2-methylpropyl. Particularly preferred are those compounds wherein R3 is cyclohexyl, 2-methylpropyl, pyridin-3-ylmethyl, 1-benzyloxyethyl, 1-methylpropyl, 1,1-dimethylethyl, 1-hydroxyethyl, and indol-2-ylmethyl; and R1 is methoxycarbonyl.
A fourth group preferred for matrilysin inhibition, are the compounds of formula (II) wherein R1 is hydroxycarbamoyl.
Within this fourth group, a preferred subgroup of compounds are those compounds wherein R2 is alkyl, aralkyl, cycloalkylalkyl; R3 is cycloalkyl or alkyl (optionally substituted by cycloalkyl, hydroxy, aralkoxy, alkylthio, pyridinyl or indolyl); R4 is cyano, hydroxy, alkoxy, carboxy, alkoxycarbonyl, alkoxycarbonylalkyl, carbamoyl (optionally substituted by aralkylaminoalkyl), or aminosulfonyl (optionally substituted by alkyl); and R5 is hydrogen.
Within this subgroup, a preferred class of compounds are those compounds wherein R2 is alkyl; R3 is cyclohexyl, alkyl (optionally substituted by cyclohexyl, hydroxy, benzyloxy, methylthio, pyridinyl or indolyl); and R4 is carboxy, alkoxycarbonyl and aminosulfonyl.
Within this class, preferred compounds are those compounds wherein R2 is 2-methylpropyl. Particularly preferred are those compounds wherein R3 is cyclohexyl, 2-methylpropyl, pyridin-3-ylmethyl, 1-benzyloxyethyl, 1-methylpropyl, 1,1-dimethylethyl, 1-hydroxyethyl, and indol-2-ylmethyl. Presently, the most preferred compounds of formula (I) are the following:
N-(2R-(Nxe2x80x3-hydroxycarbamoyl)methyl-4-(methyl)pentanoyl)-L-tryptophan-Nxe2x80x2-(4-(carboxy)phenyl)carboxamide,
N-(2R-(Nxe2x80x3-hydroxycarbamoyl)methyl-4-(methyl)pentanoyl)-L-leucine-Nxe2x80x2-(4-(methoxycarbonyl)phenyl)carboxamide;
N-(2R-(Nxe2x80x3-hydroxycarbamoyl)methyl-4-(methyl)pentanoyl)-L-leucine-Nxe2x80x2-(4-(carboxy)phenyl)carboxamide;
N-(2R-mercaptomethyl-4-(methyl)pentanoyl)-L-leucine-Nxe2x80x2-(4-(methoxycarbonyl)phenyl)carboxamide;
N-(2R-acetylthiomethyl-4-(methyl)pentanoyl)-L-leucine-Nxe2x80x2-(4-methoxycarbonylphenyl)carboxamide;
N-(2R-carboxymethyl-4-(methyl)pentanoyl)-L-leucine-Nxe2x80x2-(4-(methoxycarbonyl)phenyl)carboxamide;
N-(2R-(Nxe2x80x3-hydroxycarbamoyl)methyl-4-(methyl)pentanoyl)-L-cyclohexylglycine-Nxe2x80x2-(4-(methoxycarbonyl)phenyl)carboxamide;
N-(2R-(Nxe2x80x3-hydroxycarbamoyl)methyl-4-(methyl)pentanoyl)-L-t-leucine-Nxe2x80x2-(4-(methoxycarbonyl)phenyl)carboxamide;
N-(2R-(N-hydroxycarbamoyl)methyl-5-(biphen-4-yl)pentanoyl-L-t-leucine-Nxe2x80x2-(pyrid-4-yl)carboxamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-t-leucine-Nxe2x80x2-(pyridin-4-yl)carboxamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-t-leucine-Nxe2x80x2-(4-((2-hydroxyethyl)aminosulfonyl)phenyl)carboxamide;
N-(2R-carboxymethyl-5-(4-(pyrid-4-yl)phenyl)pentanoyl)-L-leucine-Nxe2x80x2-(4-(methoxycarbonyl)phenyl)carboxamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-xcex2-hydroxyvaline-Nxe2x80x2-(phenyl)carboxamide;
N-(Nxe2x80x3-formyl-Nxe2x80x3-hydroxyamino)methyl-5-(biphen-4-yl)pentanoyl)-L-t-leucine-Nxe2x80x2-(pyridin-4-yl)carboxamide;
N-(2R,S)-(Nxe2x80x3-formyl-Nxe2x80x3-hydroxyamino)methyl-4-(methyl)pentanoyl)-L-leucine-Nxe2x80x2-(4-(methoxycarbonyl)phenyl)carboxyamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-t-leucine-Nxe2x80x2-(4R,S-(methylsulfinyl)phenyl)carboxamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-t-leucine-Nxe2x80x2-(4-(methylaminosulfonyl)phenyl)carboxamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-t-leucine-Nxe2x80x2-(4-(3-(morpholin-4-yl)propylaminosulfonyl)phenyl)carboxamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-cyclohexylglycine-Nxe2x80x2-(4-((2-hydroxyethyl)aminosulfonyl)phenyl)carboxamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-cyclohexylglycine-Nxe2x80x2-(4((2-(dimethylamino)ethyl)aminosulfonyl)phenyl)carboxamide;
N-(2R-(Nxe2x80x3-hydroxycarbamoyl)methyl-4-(methyl)pentanoyl) D,L-norvaline-Nxe2x80x2-(4-(dimethylaminoethylcarbamoyl)phenyl)carboxamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-lysine-Nxe2x80x2-(4-(ethoxycarbonyl)phenyl)carboxamide;
N-(2R-carboxymethyl-5-(phenyl)pentanoyl)-L-lysine-Nxe2x80x2-(4-(ethoxycarbonyl)phenyl)carboxamide;
N-(2R-carboxymethyl-5-(biphen-4-yl)pentanoyl)-L-(Nxcex5-isopropyl)lysine-Nxe2x80x2-(4-(ethoxycarbonyl)phenyl)carboxamide;
N-(2R-carboxymethyl)-4-(phenyl)butanoyl)-L-cyclohexylglycine-Nxe2x80x2-(4-(Nxe2x80x3,Nxe2x80x3-dimethylaminoethylaminosulfonyl)-phenyl)carboxamide; and
N-(2R-carboxymethyl-5-(phenyl)pentanoyl)-L-(N,Nxe2x80x2-diethylguanido)lysine-Nxe2x80x2-(4-(ethoxycarbonyl)phenyl)carboxamide.
The compounds of formula (I) are prepared as described below, for example with reference to Reaction Schemes 1-7, in which the substituent groups illustrated (e.g., R1, R2, etc.) have the same meanings as described in the Summary of the Invention, unless otherwise specified. Certain of the reaction schemes illustrate structures of formula (I) where p is zero and R7 is an optionally substituted phenyl group [the substituents R4 and R5 having been described in connection with formula (II) in the Summary of the Invention). As those skilled in the art will appreciate, while the corresponding compounds where p is 1-4 and where R7 is as otherwise defined can be analogously prepared, combinations of substituents and/or variables in compounds of formula (I) and intermediates thereof are permissible only when such combinations result in stable compounds.
Compounds of formula. (I) and their pharmaceutically acceptable salts, as single stereoisomers or as mixtures thereof, are peptide derivatives all or portions of which can be prepared from the constituent xcex1-amino acid derivative(s). Standard methods for the formation of peptide bonds are illustrated by M. Bodanszky et al., The Practice of Peptide Synthesis (1984), Springer-Verlag; M. Bodanszky, Principles of Peptide Synthesis (1984), Springer-Verlag; J. P. Greenstein et al., Chemistry of the Amino Acids (1961), Vol. 1-3, John Wiley and Sons Inc.; G. R. Pettit, Synthetic Peptides (1970), Vol. 1-2, Van Nostrand Reinhold Company.
The terms xe2x80x9csolventxe2x80x9d, xe2x80x9cinert organic solventxe2x80x9d or xe2x80x9cinert solventxe2x80x9d mean a solvent inert under the conditions of the reaction being described in conjunction therewith [including, for example, benzene, toluene, acetonitrile, tetrahydrofuran (xe2x80x9cTHFxe2x80x9d), dimethylformamide (xe2x80x9cDMFxe2x80x9d), chloroform, methylene chloride (or dichloromethane), diethyl ether, methanol, pyridine and the like]. Unless specified to the contrary, the solvents used in the reactions of the present invention are inert organic solvents.
The term xe2x80x9cq.s.xe2x80x9d means adding a quantity sufficient to achieve a stated function, such as to bring a solution to a desired volume.
Unless specified to the contrary, the reactions described herein take place at atmospheric pressure within a temperature range from 5xc2x0 C. to 100xc2x0 C. (preferably from 10xc2x0 C. to 50xc2x0 C.; most preferably at xe2x80x9croomxe2x80x9d or xe2x80x9cambientxe2x80x9d temperature, e.g., 20xc2x0 C.). Further, unless otherwise specified, the reaction times and conditions are intended to be approximate, e.g., taking place at about atmospheric pressure within a temperature range of about 5xc2x0 C. to about 100xc2x0 C. (preferably from about 10xc2x0 C. to about 50xc2x0 C.; most preferably about 20xc2x0 C.) over a period of about 1 to about 10 hours (preferably about 5 hours). Parameters given in the Examples are intended to be specific, not approximate.
Amide couplings used to form the compounds of formula (I) are generally performed by the carbodiimide method with reagents such as dicyclohexylcarbodiimide or Nxe2x80x2-ethyl-Nxe2x80x2-(3-dimethylaminopropyl)-carbodiimide (EDCI) in the presence of 1-hydroxybenzotriazole (HOBT) in an inert solvent such as dimethylformamide (DMF). Other methods of forming the amide or peptide bond include, but are not limited to synthetic routes via an acid chloride, acyl azide, mixed anhydride or activated ester such as nitrophenyl ester. Typically, solution phase amide couplings with or. without peptide fragments are performed.
The selection of protecting groups for the terminal amino or carboxy groups of compounds used in the preparation of the compounds of formula (I) is dictated in part by the particular amide or peptide coupling conditions, and in part by the amino acid and/or peptide components involved in the coupling. Amino-protecting groups commonly used include those which are well known in the art, e.g., p-methoxybenzyloxycarbonyl, benzyloxycarbonyl (also referred to as carbobenzyloxy or CBZ), p-nitrobenzyloxycarbonyl, t-butoxycarbonyl (BOC), and the like. It is preferred to use either BOC or CBZ as the protecting group for the xcex1-amino group because of the relative ease of its removal by mild acids [e.g., by trifluoroacetic acid (TFA) or hydrochloric acid in ethyl acetate] or by catalytic hydrogenation.
Isolation and purification of the compounds and intermediates described herein can be effected, if desired, by any suitable separation or purification procedure such as, for example, filtration, extraction, crystallization, column chromatography, thin-layer chromatography or thick-layer chromatography, or a combination of these procedures. Specific illustrations of suitable separation and isolation procedures can be had by reference to the examples hereinbelow. However, other equivalent separation or isolation procedures can, of course, also be used.
The individual stereoisomers of compounds of formula (I) may be separated from each other by methods known to those of ordinary skill in the art, e.g., by selective crystallization or by chromatography, and/or by the methods disclosed herein.
Compounds of formula (E) are intermediates used in the preparation of compounds of formula (I), and are prepared as shown in Reaction Scheme 1 wherein R12 is mesyl or tosyl: 
Starting Materialsxe2x80x94Compounds of formula (Ea) may be prepared according to methods known to those of ordinary skill in the art (e.g., see European Published Patent Application 0 276 436) or may be prepared according to the method described in Example 1 below. Compounds of formula (Ed) are commercially available or may be prepared according to methods known to those of ordinary skill in the art.
Formula (Eb)xe2x80x94In general, compounds of formula (E) are prepared by first treating a compound of formula (Ea) in an aprotic solvent, preferably tetrahydrofuran and methylene chloride, at 0-15xc2x0 C., preferably at 0xc2x0 C., in the presence of a base, preferably diisopropylethylamine and bis-(trimethylsilyl)-acetamide, with paraformaldehyde. The resulting solution is brought to 25-37xc2x0 C., preferably to 37xc2x0 C., for 18 hours. The alcohol of formula (Eb) is then isolated by standard methods, preferably by evaporation of solvent, extraction and filtration.
Formula (Ec)xe2x80x94An alcohol of formula (Eb) in an aprotic solvent, preferably methylene chloride, is then cooled to xe2x88x9220xc2x0 C. to about 0xc2x0 C., preferably to about xe2x88x9220xc2x0 C., and is then esterified by the standard procedure of treating the alcohol with at least a stoichiometric amount to about a 100% excess of either mesyl chloride or tosyl chloride. The esterification takes place over an initial period of time (preferably 15 minutes) at xe2x88x9220xc2x0 C., followed by second period of time (preferably 3.5 hours) at room temperature. The ester of formula (Ec) is then isolated from the reaction mixture by standard isolation procedures, preferably by extraction, filtration and evaporation.
Formula (Ed)xe2x80x94An ester of formula (Ec) in an aprotic solvent, preferably DMF, is then reacted with a salt of a compound of formula (Ed) (preferably the sodium salt formed from the reaction of the compound of formula (Ed) with sodium hydride in an aprotic solvent, preferably DMF), for about 16-20 hours, preferably for about 18 hours, at temperatures beginning at about 0xc2x0 C. and slowly warming to room temperature. The resulting mercapto compound of formula (Ee) is isolated from the reaction mixture by standard isolation techniques, such as by extraction, evaporation, and flash chromatography.
Formula (E)xe2x80x94A compound of formula (Ee) is then hydrolyzed under basic conditions, preferably in the presence of sodium hydroxide, to form a compound of formula (E), which is isolated from the reaction mixture by standard isolation techniques.
Compounds of formula (Ia) are compounds of formula (I) wherein R1 is a group of the formula 
(where, when R6 is aryl it is preferably naphth-1-yl, naphth-2-yl or phenyl, and when R6 is heteroaryl it is preferably pyridyl or quinol-2-yl; R2 is preferably alkyl; and R3 is preferably hydrogen) are prepared as described in Reaction Scheme 2. 
Starting Materialsxe2x80x94N-protected amino acids of formula (A) and compounds of formula (B) are commercially available or may be prepared according to methods known to those of ordinary skill in the art. Compounds of formula (E) are prepared as described with reference to Reaction Scheme 1.
Formula (C)xe2x80x94In general, compounds of formula (Ia) are prepared by first coupling a compound of formula (A) with a compound of formula (B) [or with another compound of the formula H2Nxe2x80x94(CH2)pxe2x80x94R7], under standard amide coupling. conditions to form a compound of formula (C). For example, to a cold (0-5xc2x0 C.) solution of the compound of formula (A) and an excess molar amount of HOBT in DMF is added an excess molar amount of EDCI. The resulting solution is stirred from about 1 to about 2 hours, preferably for about 1 hour, at 0-5xc2x0 C., preferably at 0xc2x0 C. To the cold solution is then added a solution of an equimolar amount of a compound of formula (B) in the presence of a base, preferably DMAP. The resulting mixture is stirred from. 12 to 24 hours, preferably for 24 hours, at room temperature, preferably at 25xc2x0 C. The compound of formula (C) is then isolated from the reaction mixture by standard peptide isolation techniques.
Formula (D)xe2x80x94The amino-protecting group of the compound of formula (C) is then removed under mild acidic conditions, preferably in the presence of trifluoroacetic acid, to yield a compound of formula (D).
Alternative Preparations of Formula (D)xe2x80x94Another method of preparing a compound of formula (D) particularly when R3 is t-butyl, other xcex2-branched amino acid side chains, or cyclohexyl, p is zero, and R7 is aryl or heteroaryl, employs the intermediate (A-1), the preparation of which is illustrated in Reaction Scheme 2A. Another alternative method of preparing a compound of formula (D) particularly when R3 is 1-hydroxyisopropyl or another xcex2-hydroxy amino acid side chain, and R7 is aryl or heteroaryl, is illustrated in Reaction Scheme 2B. 
As illustrated in Reaction Scheme 2A, a compound of formula (A) is coupled with about one molar equivalent of N-hydroxysuccinimide in acetonitrile at 0xc2x0 C. in the presence of DCC. The reaction takes place with stirring at 0xc2x0 C. to 25xc2x0 C., for 8 to 16 hours to give the corresponding N-hydroxysuccinimide ester of formula (A-1). This ester is then reacted with a compound of formula B or another compound of the formula H2Nxe2x80x94(CH2)pxe2x80x94R7 in an inert solvent at 100xc2x0 C. preferably for 3 hours the resultant compound of formula (C) is isolated and deprotected to yield a compound of formula (D) as described above in Reaction Scheme 2. 
As illustrated in Reaction Scheme 2B, a compound of formula (C-1) in an inert anhydrous solvent such as THF is stirred with n-butyllithium at a temperature below 10xc2x0 C., preferably 0xc2x0 C., for about 1 hour, then cooled to about xe2x88x9270xc2x0 C. and reacted with 3 molar equivalents of acetone. A compound of formula (C-2), as a racemate, is isolated and purified by standard procedures. Following hydrogenolytic removal of the CBZ protecting group, a compound of formula (D-1) is obtained.
Formula (Ia)xe2x80x94As illustrated in Reaction Scheme 2, a compound of formula (D) is coupled with a compound of formula (E) under standard peptide coupling conditions. For example, to a cold (0-5xc2x0 C., preferably 0xc2x0 C.) solution of the compound of formula (D) in an inert solvent, preferably THF, is added 1,1xe2x80x2-carbonyldiimidazole. The resulting mixture is stirred from 60 to 90 minutes, preferably for 75 minutes, at 0-5xc2x0 C., preferably at 0xc2x0 C., and then reacted with the compound of formula (E) for about 12 to 17 hours, preferably for about 15 hours. The resulting compound of formula (Ia) is then isolated from the reaction mixture by standard peptide isolation techniques, for example, extraction and reverse phase HPLC.
Compounds of formula (F): 
where R8 is t-butyl, are intermediates used in the preparation of compounds of formula (I) as illustrated below in Reaction Scheme 4. The compounds of formula (F) are prepared as shown in Reaction Scheme 3. 
Starting Materialsxe2x80x94Compounds of formula (Fa) are commercially available or may be prepared according to methods known to those of ordinary skill in the art, for example, by the method described in Example 11 below. L-(+)-2,10-Camphor sultam and D-(xe2x88x92)-2,10-camphor sultam are commercially available, for example, from Aldrich.
Formula (Fb)xe2x80x94In general, compounds of formula (F) (illustrated as one of the two isomers obtainable by this synthesis) are prepared by first condensing a compound of formula (Fa) [where the group R2 encompasses the group xe2x80x9cXxe2x80x9d of Formula (I) and can be, e.g., a biphenylpropylene or fluorenyl propylene group] with L-(+)-2,10-camphor sultam to form a compound of formula (Fb).
Formula (Fc)xe2x80x94Using sodium hexamethyldisilazide to generate the anion for 1 hour, the reaction is quenched with t-butylbromoacetate to form the corresponding ester of formula (Fc).
Formula (F)xe2x80x94The camphor group is then removed under basic conditions, such as lithium hydroperoxide (formed in situ from lithium hydroxide and hydrogen peroxide) initially at reduced temperature (preferably 0xc2x0 C.) for 15 minutes and warmed to room temperature for 2 hours. The mixture is cooled back to 0xc2x0 C. and an aqueous mixture of sodium sulfite and sodium bicarbonate is added with stirring, after which the mixture is allowed to return to room temperature, and the pH is neutralized to yield an individual stereoisomer of a compound of formula (F) wherein the carbon to which the xe2x80x94Xxe2x80x94R2 group is attached is in the (R) configuration. In a similar manner, but substituting D-(xe2x88x92)-2,10-camphor sultam for L-(+)-2,10-camphor sultam, the corresponding individual stereoisomers in the (S) configuration can be prepared.
Alternative Preparation of Formula (F)xe2x80x94Another method of preparing stereoisomers of formula (F) utilizes the commercially available chiral compound, 4S-phenylmethyloxazolidinone, as shown below in Reaction Scheme 3A (following the Starting Materials section, where preparation of the compounds of starting material of formula (Faxe2x80x2) are illustrated].
Compounds of formula (Faxe2x80x2) where X is xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94 are prepared as illustrated in Reaction Scheme 3A-1. 
A commercially-available alcohol (a) is reacted with ethyl-4-bromocrotonate (b) in the presence of stoichiometric sodium hydride in a solvent such as DMF at 0xc2x0 C. to room temperature, or in the case of a phenol (a), by refluxing with (b) in acetone in the presence of excess potassium carbonate for several hours. The resulting unsaturated ester (c) is converted by hydrogenation in the presence of platinum on carbon to the saturated ester (d), which is then saponified with aqueous sodium hydroxide in ethanol to the acid (e). The acid (e) is converted to the acid chloride (Faxe2x80x2-1) through the action of oxalylchloride at between room temperature and 50xc2x0 C.
Compounds of formula (Faxe2x80x2) where X is xe2x80x94Sxe2x80x94CH2CH2xe2x80x94 are prepared as illustrated in Reaction Scheme 3A-2. 
A commercially-available thiol (f) is reacted with lithium hydride in DMF at room temperature for several hours to form the lithium thiolate. Excess butyrolactone (g) is added and heated to reflux under argon to give the acid (h). Acid (h) is then converted to the acid chloride (Faxe2x80x2-2) with oxalyl chloride, as before.
Compounds of formula (Faxe2x80x2) where X is xe2x80x94CH2CH2xe2x80x94Oxe2x80x94 are prepared as illustrated in Reaction Scheme 3A-3. 
Compounds of formula (l) and (k) are in many cases commercially available. When not, they are prepared as follows. Compounds of formula (j), where R2 is aryl or heteroaryl, are converted to alkenes (k) by treatment for several hours with vinyl-tributylstannane (commercially available from Aldrich Chemical Co.) in the presence of catalytic tetrakis (triphenylphosphine)palladium at reflux in toluene. The alkenes (k) may be further converted to the alcohols (l) by hydroboration with borane in THF at 0xc2x0 C. to room temperature, over a period of several hours, followed by oxidation with alkaline hydrogen peroxide. The alcohols (l) are converted to the acids (m) by treatment with chloroacetic acid and excess sodium hydride in DMF at elevated temperature, preferably 60xc2x0 C. The acids (m) are converted to the acid chlorides (Faxe2x80x2-3) with oxalyl chloride, as before.
Compounds of formula (Faxe2x80x2) where X is xe2x80x94CH2CH2xe2x80x94Sxe2x80x94 are prepared according to Reaction Scheme 3A-4. 
The alcohols (l) are converted to thioacetates (n) by addition of thioacetic acid to the reagent generated from triphosphine and diethyl azodicarboxylate in THF at 0xc2x0 C. The thioacetates (n) are converted to the acids (p) by treatment with potassium carbonate in methanol in the presence of chloroacetic acid. The acids (p) are converted to the acid chloride (Faxe2x80x2-4) with oxalyl chloride, as before. 
Formula (Fbxe2x80x2)xe2x80x94A compound of formula (Faxe2x80x2) is first condensed with 4S-phenylmethyloxazolidinone under standard conditions to give the corresponding compound of formula (Fbxe2x80x2).
Formula (Fcxe2x80x2)xe2x80x94An approximately equimolar amount of sodium hexamethyldisilazide is added to a compound of formula (Fbxe2x80x2) in an inert solvent such as THF. The reaction takes place at xe2x88x9280xc2x0 C. to xe2x88x9295xc2x0 C., for about 15 minutes. t-Butylbromoacetate is added in excess to this mixture and the solution is stirred for about 2 hours at xe2x88x9290xc2x0 C. to xe2x88x9260xc2x0 C. to yield a single stereoisomer of formula (Fcxe2x80x2), which is purified by standard organic chemistry procedures.
Formula (Fxe2x80x2)xe2x80x94The oxazolidinone group of a compound of formula (Fcxe2x80x2) is removed under basic conditions to yield an individual stereoisomer of formula (Fxe2x80x2), for example as described with reference to the preparation of formula (F) in Reaction Scheme 3. The compounds of formula (Fxe2x80x2) can be used interchangeably with those of formula (F) in the syntheses that follow.
Alternative Preparation of Formula (F)xe2x80x94Formula F can also be prepared as described with reference to Reaction Scheme 3B. 
Starting Materialsxe2x80x94The compound illustrated as formula (Fcxe2x80x3) can be prepared analogously to the preparation of formula (Fcxe2x80x2) as described with reference to Reaction Scheme 3A, by substituting for the compound of formula (Faxe2x80x2) the corresponding allyl compound where the group shown as X is prop-2-enyl and R2 is H.
Formula (Fcxe2x80x3-1)xe2x80x94Arylation or heteroarylation of (Fcxe2x80x3) is carried out in the presence of a base and a palladium catalyst by adding aryl- or heteroaryl-halide, preferably bromide or iodide, and heating the reaction mixture for about 2 to 4 hours, preferably 4 hours, at about 100xc2x0 C. to form a compound of the formula (Fcxe2x80x3-1).
Formula (Fcxe2x80x3-2)xe2x80x94Catalytic hydrogenation (Pd/C) of an allyl compound of formula (Fcxe2x80x3-1) yields the corresponding alkyl compound of the formula (Fcxe2x80x3-2).
Formula (F)xe2x80x94A compound of formula (Fcxe2x80x3-2) is subjected to basic conditions, such as lithium hydroperoxide (formed in situ from lithium hydroxide and hydrogen peroxide) initially at reduced temperature (preferably 0xc2x0 C.) for 15 minutes and warmed to room temperature for 2 hours. The mixture is cooled back to 0xc2x0 C. and an aqueous mixture of sodium sulfite and sodium bicarbonate is added with stirring, after which the mixture is allowed to return to room temperature, the pH neutralized, and the compound of formula (F) is obtained by standard isolation.
The compounds of formulae (Ib), (Ic), (Id) and (Ie) each represent sub-genuses of formula I in which the R1 substituent varies, prepared sequentially as described in Reaction Scheme 4, where R8 is t-butyl. In compounds of formula (Ib) R1 is alkoxycarbonyl or aralkoxycarbonyl. In compounds of formula (Ic) R1 is carboxy. In compounds of formula (Id) R1 is benzyloxycarbamoyl. In compounds of formula (Ie) R1 is hydroxycarbamoyl. 
Starting Materialsxe2x80x94Formula (D) is prepared as described with reference to Reaction Schemes 2, 2A and 2B. Formula (F) is prepared as described with reference to Reaction Schemes 3 and 3A. O-Benzylhydroxylamine is commercially available, for example, as the hydrochloride salt from Aldrich Co.
Formula (Ib)xe2x80x94A compound of formula (F) is cooled with a compound of formula (D) under standard amide coupling conditions to form a compound of formula (Ib). For example, to a solution of a compound of formula (F) in an aprotic solvent, preferably DMF, containing a slightly excess molar amount of HOBT, is added an excess molar amount of EDCI. The resulting mixture is stirred from 1 to 2 hours (preferably 1 hour) at 0-5xc2x0 C. (preferably at 0xc2x0 C.). To the cold solution is then added an equimolar amount of a compound of formula (D) in the presence of a base, preferably DMAP. The resulting mixture is then stirred from 12 to 24 hours (preferably 24 hours) at room temperature (preferably at 25xc2x0 C.). The compound of formula (Ib) is then isolated from the reaction mixture by standard peptide isolation techniques, for example, evaporation of solvents, extraction, flash chromatography and/or HPLC.
Formula (Ic)xe2x80x94A compound of formula (Ib) is hydrolyzed under mild acidic conditions, preferably with trifluoroacetic acid, to yield a compound of formula (Ic).
Formula (Id)xe2x80x94A compound of formula (Ic) is then treated with O-benzylhydroxylamine under standard amide coupling conditions to form a compound of formula (Id). For example, a cold (0-5xc2x0 C.) solution of the compound of formula (Ic) and HOBT in an inert solvent, preferably DMF, is treated with an excess molar amount of EDCI. After stirring the resulting mixture for 30 minutes to an hour at 0-5xc2x0 C. (preferably at 0xc2x0 C.), an equimolar amount of O-benzylhydroxyamine is added. The reaction mixture is allowed to warm and remain at room temperature overnight for 8 to 16 hours. The compound of formula (Id) is then isolated from the reaction mixture by standard isolation techniques, for example, by extraction and flash chromatography.
Formula (Ie)xe2x80x94The hydroxyl-protecting group (benzyl) of a compound of formula (Id) is removed under catalytic hydrogenation conditions (Pd/C) to yield a compound of formula (Ie).
Alternative Preparation of Formula (Ie)xe2x80x94An alternative method for preparing formula (Ie) (particularly where R4 is a sulfur-containing moiety, such as alkylsulfinyl) is to treat the corresponding compound of formula (Ic) with hydroxylamine hydrochloride and a peptide coupling reagent, preferably benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate, in the presence of a tertiary amine base such as N-methylmorpholine in DMF solvent. The resulting compound of formula (Ie) is isolated from the reaction mixture by standard isolation techniques, for example, by extraction and concentration.
Alternative Preparation of Formula (Ib)xe2x80x94A particularly preferred method of preparing compounds of formula (Ib) when R2 is an aryl or heteroaryl, and where X (not shown) is propanyl and p (not shown) is zero is shown in Reaction Scheme 4A. 
Starting Materialsxe2x80x94The compound illustrated as formula (Fcxe2x80x3) can be prepared analogously to the preparation of formula (Fcxe2x80x2) as described with reference to Reaction Scheme 3A, by substituting for the compound of formula (Faxe2x80x2) the corresponding allyl compound where R2 is prop-2-enyl. The compound of formula (Dxe2x80x2) is a compound of formula (D) and can be as described in Reaction Scheme 2. The halo-aryl or halo-heteroaryl reactants used in the preparation of compounds of formula (Dxe2x80x2-2) are commercially available, or can be prepared according to methods known to those of ordinary skill in the art, e.g., as described in Example 41C.
A compound of formula (Fxe2x80x3) is prepared by alkaline hydrolysis of the oxazolidinone group from a compound of formula (Fcxe2x80x3). After isolation by standard procedures, (Fxe2x80x3) is coupled with a compound of formula (Dxe2x80x2) under standard peptide coupling conditions as described above with reference to Reaction Scheme 2, to form a compound of formula (Dxe2x80x2-1). Arylation or heteroarylation of (Dxe2x80x2-1) is accomplished by adding aryl- or heteroaryl-halide (preferably aryl- or heteroaryl bromide, iodide or triflate) and heating the reaction mixture for about 2 hours at about 100xc2x0 C. to form a compound of the formula (Dxe2x80x2-2). Catalytic hydrogenation (Pd/C) of (Dxe2x80x2-2) yields a compound of formula (Ibxe2x80x2).
Compounds of formula (G): 
are intermediates in the preparation of compounds of formula (I) and are prepared as illustrated below in Reaction Scheme 6. The compounds of formula (G) are prepared as shown in Reaction Scheme 5. 
Starting Materialsxe2x80x94Compounds of formula (Ga) and thioacetic acid are commercially available, for example, from TCI America Organic Chemicals and the Aldrich Company, respectively.
Formula (Gb)xe2x80x94A compound of formula (Ga) is hydrolyzed with an equimolar amount of a base, for example, potassium hydroxide, to yield a compound of formula (Gb).
Formula (Gc)xe2x80x94A compound of formula (Gb) is deprotonated under basic conditions, for example, in the presence of triethylamine, at 0-5xc2x0 C. (preferably at 0xc2x0 C.) and then reacted with formaldehyde, followed by treatment with aqueous base, preferably potassium carbonate, to yield a compound of formula (Gc), which is isolated from the reaction mixture by standard isolation procedures.
Formula (Gd)xe2x80x94A compound of formula (Gc) is hydrolyzed under basic conditions, preferably in the presence of lithium hydroxide, to yield a compound of formula (Gd).
Formula (G)xe2x80x94A compound of formula (Gd) is reacted with an excess molar amount of thioacetic acid at 90-100xc2x0 C. (preferably at 95xc2x0 C.) under an inert atmosphere. The compound of formula (G) is then isolated from the reaction mixture by standard isolation techniques, for example, by extraction and evaporation.
The compounds of formulae (If) and (Ig) each represent sub-genuses of formula I in which the R1 substituent is sulfur-containing, prepared sequentially as described in Reaction Scheme 6. In compounds of formula (If), R1 is acetylthio. In compounds of formula (Ig), R1 is mercapto. 
Formula (If)xe2x80x94A compound of formula (G) is coupled with a compound of formula (D) under standard amide coupling conditions to yield a compound of formula (If). For example, to a solution of the compound of formula (G) and HOBT in an aprotic solvent, preferably DMF, is added an excess molar amount of EDCI. Subsequently, the compound of formula (D) is added and the resulting mixture is stirred overnight at room temperature. The resulting compound of formula (If) is then isolated from the reaction mixture by standard isolation techniques, for example, by evaporation of solvent, extraction, and flash chromatography.
Formula (Ig)xe2x80x94A compound of formula (If) is hydrolyzed under basic conditions, preferably in a protic solvent such as methanol in the presence of ammonium hydroxide, to form a compound of formula (Ig).
Compounds of formula (Ih) are a sub-genus of formula (I) where R1 is N-hydroxyformamide, and are prepared as shown in Reaction Scheme 7. 
Starting Materialsxe2x80x94The compound illustrated as formula (Fbxe2x80x3) can be prepared analogously to the preparation of formula (Fbxe2x80x2) as described with reference to Reaction Scheme 3A, by substituting for the compound of formula (Faxe2x80x2) the corresponding allyl compound where R2 is prop-2-enyl.
Formula (P-1)xe2x80x94The compound of formula (Fbxe2x80x3) is hydroxymethylated by incubation with titanium tetrachloride at reduced temperature, preferably 0xc2x0 C., under basic conditions for one to three hours, preferably 1 hour followed by addition of S-trioxane and titanium tetrachloride with continued incubation at 0xc2x0 C. for 3 to 5 hours, preferably 4 hours. The compound of formula (P-1) is then isolated by standard methods, e.g., extraction and column chromatography.
Formula (P-2)xe2x80x94The compound of formula (P-1) is reacted with an excess molar amount of 0-benzylhydroxylamine and of trimethylaluminum at reduced temperature, preferably 0xc2x0 C. The reaction is allowed to proceed with stirring for 5 to 7 hours, preferably 6 hours, at 0xc2x0 C. under argon. The resulting compound of formula (P-2) is isolated by standard procedures.
Formula (P-3)xe2x80x94Excess mesyl chloride is reacted with the compound of formula (P-2) in pyridine at 0xc2x0 C. for several hours, preferably 3 hours. The reaction mixture is cooled on ice, organic solvent-extracted, and concentrated. The concentrated extract is refluxed under basic conditions for several hours, preferably 3 hours, thus yielding the azetidinone compound of formula (P-3), which is purified by standard procedures.
Formula (P-4)xe2x80x94The compound of formula (P-3) is reacted with a desired halogenated R2 group (e.g., an aryl- or heteroaryl halide, preferably -bromide or iodide) in an inert solvent in the presence of a base, such as triethylamine, and a palladium catalyst, preferably formed from palladium (II) acetate and about 2 molar equivalents of tri-o-tolylphosphine. After heating the reaction mixture for 15 to 20 hours, preferably 18 hours at 100xc2x0 C., the corresponding compound of formula (P-4) is isolated and purified by standard procedures.
Formula (P-5)xe2x80x94Cleavage of the azetidinone ring of a compound of formula (P-4) is carried out under basic conditions at room temperature for 1 to 3 hours, preferably 1 hour. The resultant compound is extracted into organic solvent, concentrated, redissolved in a base-containing solvent (e.g., pyridine), and carboxylated with formic anhydride at reduced temperature, preferably 0xc2x0 C., for 30 minutes, to yield the corresponding compound of formula (P-5), which is isolated by standard procedures.
Formula (P-6)xe2x80x94A compound of formula (P-5) is coupled with a compound of formula (Dxe2x80x2) under standard amide coupling conditions to form the corresponding compound of formula (P-6), which is isolated by standard procedures.
Formula (Ih)xe2x80x94Catalytic hydrogenation of a compound of formula (P-6) with Pd/C, followed by removal of the catalyst by filtration yields the corresponding compound of formula (Ih).
In addition, all compounds of formula (I) that exist in either the free acid or the free base form may be converted to their pharmaceutically acceptable salts by treatment with the appropriate inorganic or organic base or with the appropriate inorganic or organic acid, respectively. Salts of the compounds of formula (I) can also be converted to the free acid or free base form or to another salt. For example, a compound of formula (I) having a carboxylic acid moiety can be converted to the carboxylate form by addition of 1 equivalent of NaOH or KOH in an alcoholic solvent followed by evaporation of solvent. A compound of formula (I) in the form of a free base can be converted to the chloride salt, for example, by addition of 1 equivalent of HCl in an organic solvent, followed by concentration.
In summary, compounds of formula (I) are prepared by:
(A) contacting a compound of formula (D) 
xe2x80x83with a compound of formula (F) 
xe2x80x83where R1 is alkoxycarbonyl, aralkoxycarbonyl, aryl- or heteroaryl-thiomethylphosphinoyl, or acetylthio;
in the presence of a base and an amide coupling reagent to give the corresponding compound of formula (I); or
(B) catalytically hydrogenating the corresponding compound where X and R2 together are optionally aryl- or heteroaryl-substituted alkenyl; or
(C) treating a compound of formula (I), where R1 is alkoxycarbonyl or aralkoxycarbonyl, under mild acidic conditions to give the corresponding compound of formula (I) where R1 is carboxy; or
(D) contacting a compound of formula (I), where R1 is carboxy, with O-benzylhydroxylamine to give the corresponding compound of formula (I) where R1 is benzyloxycarbamoyl; or
(E) catalytically hydrogenating a compound of formula (I), where R1 is benzyloxycarbamoyl, to give the corresponding compound of formula (I) where R1 is hydroxycarbamoyl; or
(F) contacting a compound of formula (I), where R1 is carboxy, with hydroxylamine to give the corresponding compound of formula (I) where R1 is hydroxycarbamoyl; or
(G) catalytically hydrogenating a compound of the formula 
xe2x80x83where BnO is benzyloxy, to give the corresponding compound of formula (I) where R1 is N-hydroxyformamide; or
(H) treating a compound of formula (I), wherein R1 is acetylthio, with ammonium hydroxide in a protic solvent to give the corresponding compound of formula (I) where R1 is mercapto.
A preferred method of making compounds of formula (I) where R1 is N-hydroxyformamide entails converting a compound of formula (P-4) 
wherein R2 is aryl or heteroaryl, by basic hydrolysis followed by formylation to give a compound of formula (P-5) 
reacting the compound of formula (P-5) with a compound of formula (D) to give a compound of formula (P-6) 
and catalytically hydrogenating the compound of formula (P-6).
Compounds prepared by the above-described process of the invention may be identified by the presence of a detectable amount of one or more compounds of formulae (P-3), (P-4) or (P-6). While it is well known that pharmaceuticals must meet pharmacopoeia standards before approval and/or marketing, and that synthetic reagents (such as O-benzylhydroxylamine) or precursors [such as (P-3), (P-4), or (P-6)] should not exceed the limits prescribed by pharmacopoeia standards, final compounds prepared by a process of the present invention may have minor, but detectable, amounts of such materials present, for example at levels in the range of 50 ppm or lower. These levels of (P-3) can be detected, e.g., by GC-MS, or of (P-4) can be detected, e.g., by HPLC-MS or by HPLC with fluorescence detection, or of (P-6) can be detected, e.g., by HPLC with fluorescence detection. It is important to monitor the purity of pharmaceutical compounds for the presence of such materials, which presence is additionally disclosed as a method of detecting use of a process of the invention.